Visible-light-induced,autopromoted nickel-catalyzed three-component arylsulfonation of 1,3-enynes and mechanistic insights

Science China Chemistry - A light-induced, nickel-catalyzed three-component arylsulfonation of 1,3-enynes in the absence of photocatalyst is reported. This methodology exhibited mild conditions,...     

Hierarchical motion planning at the acceleration level based on task priority matrix for space robot

Nonlinear Dynamics - A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge is to...     

Convergence of the viscosity solution of non-autonomous Hamilton-Jacobi equations

In this paper,we investigate the non-autonomous Hamilton-Jacobi equation ■ where H is 1-periodic with respect to t and M is a compact Riemannian manifold without boundary.We obtain the viscosity solution denoted by T_(t_0)~tφ(x) and show T_(t_0)~tφ(x) converges uniformly to a time-periodic viscosity solution u~*(x,t) of ?_tu+H(t,x,?_xu,u)=0.     

Stochastic relaxed inertial forward-backward-forward splitting for monotone inclusions in Hilbert spaces

Computational Optimization and Applications - We develop a globalized Proximal Newton method for composite and possibly non-convex minimization problems in Hilbert spaces. Additionally, we impose...     

g-C3N4-W18O49复合光催化剂的制备及其光催化机理研究

通过简单的溶剂热法成功制备出了g-C3N4-W18O49复合光催化剂,采用XRD、SEM、TEM以及PL对所得催化剂的物相结构及形貌和光学性能进行了表征,通过降解甲基橙和光解水产氢实验研究所得催化剂的催化性能及其催化机理.由实验可知,W18O49的含量为50;时所得g-C3N4-W18O49复合光催化剂的降解性能最好,其降解率比纯g-C3N4纳米片提高48;;为进一步研究复合光催化剂的电子-空穴传输机理,我们又进行了光解水制氢实验.结果表明:单一的W18O49无产氢活性,它的复合明显降低了g-C3N4的产氢速率,说明复合结构中光生电子是从g-C3N4传递到了W18O49,表现出明显的Ⅱ型异质结复合特征,而不是部分文献所提出的Z型方式.     

水热法制备Nd3+-介孔TiO2/GO复合材料及光催化性能研究

采用水热法首先制备稀土Nd3+掺杂介孔TiO2,进而复合氧化石墨烯(GO)合成了系列Nd3+-介孔TiO2/GO复合材料.通过X射线衍射(XRD)、透射电镜(TEM)、孔结构分析(BJH与BET)、X射线光电子能谱(XPS)和紫外-可见漫反射(UV-vis)等测试手段对样品的微观结构、形貌、样品表面各元素价态及谱学性质进行表征,并以甲基橙模拟污染物测试其光催化性能.结果表明,所制样品均为锐钛矿结构TiO2,晶粒尺寸在3~4 nm之间;从UV-vis测试结果分析可知,与Nd3+-介孔TiO2和TiO2/GO相比,稀土Nd3+和GO的协同效应更能有效减小TiO2半导体禁带宽度,从而增加其对可见光的吸收.此外,不同光照射下光催化降解甲基橙的实验表明,所制备样品均有较强的紫外及可见光光催化性能,其中系列Nd3+-介孔TiO2/GO复合体系可见光光催化性能更为显著.     

Qualitative and quantitative determination of Atractylodes rhizome using ultra‐performance liquid chromatography coupled with linear ion trap–Orbitrap mass spectrometry with data‐dependent processing

A quick and effective workflow based on ultra‐performance liquid chromatography coupled with electron spray ionization and LTQ‐Orbitrap mass spectrometry (UPLC‐LTQ‐Orbitrap MS) was established for compositional analysis and screening of the characteristic compounds of three species of Atractylodes rhizome for quality evaluation. This technique was employed to determine the seven main components in Atractylodes rhizome samples. Ultimately, 78 constituents were identified; of these, seven characteristic compounds were selected for species discrimination, comprising atractylodin (63), atractylenolide I (43), atractylenolide II (49), atractylenolide III (53), atractylon (69), methyl‐atractylenolide II (54) and (4E,6E,12E)‐tetradecadecatriene‐8,10‐diyne‐1,3‐diacetate (59). The seven main compounds, including six characteristic compounds, were simultaneously determined in 29 batches of Atractylodes rhizome samples. Thus, the method validation showed acceptable results. Quantitative analysis showed significantly different contents of the seven main components among the three species of Atractylodes rhizome, which indicates possible distinctions in the pharmacological effects. This established method can simultaneously provide qualitative and quantitative results for compositional characterization of Atractylodes rhizomes and for quality control.     

Comparative analysis of the main active components and hypoglycemic effects after the compatibility of Scutellariae Radix and Coptidis Rhizoma

In this study, a rapid and highly sensitive ultra high performance liquid chromatography with triple quadrupole mass spectrometry method with the mobile phase of acetonitrile and 0.1% aqueous formic acid was established and successfully applied to comparatively analyze main active components after their compatibility. Besides, the effects of Scutellariae Radix, Coptidis Rhizoma and combined extracts on type 2 diabetic rats induced by high‐fat diet along with low dose of streptozocin were investigated. Under the optimized chromatographic conditions, good separation of seven target components was achieved within 12 min. All calibration curves exhibited good linearity (R² ≥ 0.999). The relative standard deviation of precision, repeatability and stability varied from 0.69 to 2.23, 0.98 to 2.56, and 0.92 to 2.57%, respectively. The recovery ranged from 91.11 to 105.35%. The contents of seven active components were notably reduced after compatibility; however, the hypoglycemic effect of combined extracts was stronger than single drug by decreasing the activities of fructose‐1,6‐bisphosphatase, glucose 6‐phosphatase, phosphoenolpyruvate carboxykinase and increasing the activities of glucokinase, phosphofructokinase, pyruvate kinase. Accordingly, the established analytical method was accurate and sensitive enough for quantitative evaluation of seven investigated compounds. Moreover, the combined extract had definite effects on type 2 diabetes through multiple components against multiple targets.     

Effect of the Reaction Temperature on the Removal of Diesel Particulate Matter by Ozone Injection

This study seeks to investigate the removal efficiency of particulate matter (PM) from the actual diesel exhaust at various reaction temperatures by using non-thermal plasma (NTP). The effect of the reaction temperature on removal efficiency was reflected by the change in the concentration of particles in different modes and the weight fraction of volatile organics in PM. The Arrhenius equation was used to determine the apparent activation energies E_a of the soot in PM. In addition, the difference in the oxidation reaction at various reaction temperatures and the effect of NTP on the properties of PM were discussed. After considering the decreasing ranges of the total concentration and the weight of the PM, it was determined that 120 °C is the optimal temperature choice for PM removal. The decreasing range of the total concentration reached 57.13% and 66.79% of PM was removed when the PM is measured by weight. NTP has better effect on the removal of smaller particles. The weight fraction of the volatile fraction markedly decreases after the reaction and the apparent activation energy of soot noticeably decreased. The oxidizability of the excited species in NTP was enhanced with the increase of the reaction temperature. However, the excited species concentration declined concurrently, resulting in the occurrence of the optimized range of reaction temperature. The particles were removed by the oxidation that occurred on the surface of the primary particle and the disintegration of the structure of the particles.